Smoke filter



Oct-14, 1941. J., G. TARRANT 2,258,823

l l l A SMOKE FILTER Filed Feb '7, 1938 lill,"

.INVENTOR jlAdTToRNEY atenteii Oct. 14, 1941 :UNITED STATES PATENT oFFlcSMOKE FmrEn John G. Tarrant, New York, N. Y. Application February 7,1938, Serial No. 189,159

' s claims. (01.131-208) This invention relates to improvements in \entcore to. take up moisture that would othersmoking devices, such as pipesand cigarette holders, and more particularly to improved smoke iiltersand means for using them.

It is an object of this invention to provide an improved smoke filter oflow resistance to air flow and of great efciencyin removing tarry andother objectionable matter from tobacco smoke.

Another object is to provide a lter having an impervious coating whichretains its fresh, clean outer appearance although it is made black andtarry on the inside by the-smoke.

Another object is to vprovide such a lter, hav- 'ing an imperviouscoating, with means for indicating the extent of use to which the lterhas been put.

Another object is to provide means for holding the lter whereby cloggingof the ends is prevented.

Other and further objects of this invention will be apparent from thedrawing and the fol,- lowing description and claims:

In thedrawing,

Figure 1 is a view of one modification of the improved lter of thisinvention.

Figure 2 is a sectional view of the same lter.

Figure 3 is a view of one form of the improved lter element lof thisinvention, before being rolled into the cylindrical shape in which it isused.

Figure 4 is a view of another modication of the improved filter. Thislter can be made in a continuous operation, applying spiral wrappings ofthe various layers on a moving core, and cuttingthe finished lter tubeinto suitable lengths.

Figure 5 is a sectional view of an assembly of the lter in a cigaretteholder.

Figure 6 is a sectional view of an assembly of lthe filter in a pipe.

'piece of gauze is diagrammatically illustrated in numeral I. This is ofthe type of medicinal gauze, the threads being of a loosely twistedcotton' nbre, and of such size that the open spaces wise go to the outeredges of the roll. Instead of stitching, a similar effect is gainedbyweaving the gauze in strips having an jedge more closely woven thanthe remainder, such as a thin selvage edge. In weaving larger widthsthan required 'for the filter, similar closely woven strips may be wovenat distances equal to the width required for a vfilter, and the Agauzemay then be cut into strips each having one selvage edge. Two or morelayers of gauze may also be-superimposed preparatory to making thefilter roll. Insuch case the layers maybe stitched together along oneedge, this serving to-hold them in proper position in addition jto theadvantages noted above'.

A similar roll may be prepared by folding back upon itself 'a' narrowstrip along ,one edge of the piece of gauze and stitching through thisto form a hem. Such stitching also aids in starting the roll and formsan absorbent core which also prevents channellingv of gases, asdescribed above.

In preparing the lter the gauze is brought into a loosely packed,elongated form in which the plane of the surface of the gauze issubstantially parallel to the long dimension. Thzjgauze I is preferablymade into a roll of substantially between threads is about 2 to 20 timesthe width of the thread. 'Ihis gauze is made into a roll which is thepreferred form of the lter. One or more rows of stitching 2 may beplaced along the edge of one side to serve as an aid in starting theroll.v When the thin stitched gauze is formed into a roll with thestitching at the center, this slightly compacted portion insures againstan open center of the roll and serves to prevent channelling of gases.It also serves as an absorbcylindrical shape of any suitable size for.use in a cigarette holder or pipe stem. Strips of gauze, laid roughlyparallel in a bundle, may also be drawn through'a suitable cylinder andmay be even given a slight twist in the cylinder. However, a cylindricalroll of gauze is the preferred form for this invention.

The gauze lter v3 is preferably encased in some form of protectivecoating 4 to hold it in shape both before.`a nd during use, and also toprovide a clean and dry outer surface of the used filters, thereby toprotect the hands of the user from the odorous, tarry matter filteredout of the tobacco smoke. The coating is` also substantially imperviousto the ilow of gas, thereby providing that the smoke passes through thelter from end to end. Such a coating may rbe made of waterproofed paperor of suitable synthetic materials such as cellulose acetate sheet. Thecoating may be also made of dense, highlyglazed paper which is notcompletely waterproof but is penetrated by water only slowly and withdiiculty. This coating is also preferably opaque, or practically so, toconceal from view the tarry matter which is deposited on the gauzefilter within. 'When the coating is opaque, it is preferred to providesome indication of the extent to which the filter has become fouled inuse. be accomplished by leaving one or more small openings through theopaque coating, in the form of a narrow slit preferably parallel to theaxis This may of the cylinder, i more conveniently ln the form of spacedperforations 5.

replaced, although its general outer appearance is still clean and neat,in sharp contrast to filters whose entire outer surface is stained inuse, or which are covered with a transparent coating.

A second construction of the improved filter is shown in Figure 4. Thisfilter is particularly adapted for manufacture by automatic machinery.It contains a core 1 which is preferably of absorbent material such ascotton string, upon which are wound spirally enough layers of gauze tomake up the desired thickness. In winding the strips of gauze, eachstrip should overlap itself as little as possible. The center of eachstrip is placed over an edge of the previously wound strip, each layertherebyoverlapping the joint in the next inner layer to increase therigidity of the roll. A gas and moisture-impervious coating 4 and anouter coating 6, both of which are described above in connection withFigures 1 and 2, may also be wound as spiral layers onfthe gauze roll.The coating 4 may also contain perforations 5 and the edges of thiscoating (indicated as dotted lines 8 in Figure 4) may be sealed with asuitable adhesive to prevent leakage therethrough. Another method forindicating the ex tent of usage of the filter is leave these edges 8unsealed and to wrap the outer layer strip on so that it overlaps thejoint between these edges. The penetration of moisture through thejoints of the coating 4 thus stains the outer coating 6 in a spiralline, the intensity of this stain indicating the extent of use of thefilter.

A layer of absorbent paper, preferably soft and as thin as the gauze,may be provided between layers of the gauze to permit absorption ofmoisture from the gauze and thereby to aid in keeping the openings inthe gauze clean and to maintain the baiiling action of the gauze. Ifmore than one layer of paper is used, at least one layer of gauze shouldbe between the layers of paper. A layer of absorbent paper may also beWrapped around the roll of gauze before the protective layer 4 isapplied. Such layer is indicated by the number 9 in Figure 2 and Figure4.

An example of a suitable filter material for use in the improved lter ofthis invention is medicinal gauze, preferably the soft-bered typerecommended for use as waistbands for babies. This gauze has theadvantage of being entirely antiseptic and odorless, as well asabsorbent. It also has numerous soft fibres of lint projecting from thesurface of the threads. It may be conveniently in the form of a printcloth of the following construction:

Warp-44 threads per inch of single 40's yarn.

Filling or Woof-40 threads per inch of single 30s yarn.

Width before cutting-44 inches.

Weight-'7.25 yards per pound.

The yarn is a standard, loose twist for both the warp and the filling.This cloth is then aise,

ses

bleached, washed and sterilized according to the usual practice inmaking medicinal gauze.

While the above gauze has been described in order to illustrate thisinvention. it is to be understood that the invention is not to belimited to this particular gauze, but that lt also includes the use ofother types of cloth. such as cheese-cloth, preferably soft or unsized,in which the proportion of the total area of the holes in the cloth tothe area covered by the yarn, is large, the width of the openings beingabout 2 to 20, and preferably about 3 to 5 times the width of the yarn,measured on both the warp and the filling, and

the yarn being as soft and as loosely twisted as is compatible with thenecessary strength for handling. The gauze may be made up of yarns ofother textile bres than cotton, such as wool and linen, which arepreferably soft and absorbent.

The gauze may be medicated, if desired or perfumed, to suit. theindividual taste, though this is 4 not necessary to the operation of thefilter.

vAs indicated above, it is preferred to use sterile gauze. It is alsopreferred to sterllize the completed lter rolls. This may be done afterthey are packed in the boxes in which they are to be sold, therebyassuring the purchaser of receiving clean and sterile filters.

It has been found that filters constructed in the manner describedabove, of rolls of gauze, are far'more eillcient in removing tarry andother throat-irritating matters from tobacco smoke than are even muchlarger filters of absorbent paper, cotton, or other matted fibre, orcigarette tobacco. The gauze filters also have the advantage of very lowresistance to flow of smoke so Y that the pull of the cigarette or pipebeing smoked is not objectionably increased.

Ihe close lattice-work structure oi the gauze roll not only produces avery large surface having absorbent properties, but also provides agreat number of bales, thereby causing the flow of smoke to berepeatedly and abruptly changed in direction and causing the solid andliquid matter suspended therein to be thrown against the absorbentsurfaces of the bailles. The structure of the gauze thus is such that aroll wherein the surface of each portion of gauze is contiguous `on eachside thereof with an adjoining surface of gauze or paper, providesalmost infinite bailled paths of low resistance to the flow of smoke.Even when wet by use in lfiltering smoke it does not mat together, butthe meshes remain open and the resistance to the flow of smoke is notincreased.

lSuitable means for using these filters in cigar and cigarette holdersand in pipes are illustrated in Figures 5 and 6. It is desirable thatthe ends of the filter should not be obstructed by anything coming incontact with the gauze. Anything touching the gauze at the ends of theroll causes deposition of matter at that point; this builds upsufficiently to interfere with and to obstruct partially the flow ofair. It is also desirable, particularly when using the filter in pipes,to provide means for trapping out water, tobacco particles, etc., fromthe smoke before it reaches the filter.

Referring to Figure 5 in detail, a cigarette or cigar holder is dividedin two sections, a tobacco Masses prises a bushing I3 fitted tightlyinto the member II. The front end of this bushing has an inside diameterslightly greater than the outside `di` ameter of the filter, thusproviding for free movement of the filter in and out of this section.Near the rear end of the bushing, filter holding and aligning means I4are provided by reducing the bushing to an inside diameterapproximatelythe same as the outside diameter of the filter. Thisprovides a friction t between bushing and filter suihclently tight tohold the iilter in place, to align it along the axis of the bushing, andto prevent air from by-passing the filter in passing through the holder,and s'uiiiciently loose to permit the lter to be inserted with a gentlepush and to be removed easily, as by a slight pull or even, withouttouching it, by a quick ilip of the member II. At the rear end of meansI4 is provided means I5 for stopping the lter and for spacing it fromthe end of the smoke passage I6. Means I5 may be in the form of afinger, shelf, ridge, or other projection into the reduced tube I4. Thepreferred structure is illustrated as a further reduction in diameter ofthe bushing, thereby providing a sli-:.ulder I1. This shoulder shouldpreferably be sharp edged, and flat, in a plane perpendicular to theaxis of the bushing. A blunt edged or tapering shoulder must be of muchgreater thickness to stop the end of the filter as effectively. Thethickness of this shoulder, or, in other words, the difference in radiusof the end section I5 and the section I4 of the bushing, is preferablyless than the thickness of the coating layers of the gauze roll of thefilter, and is suitably about one-half this thickness. Sections I4 andI5 may each have a length about equal to the diameter of the lter tubeI2.

Means for connecting the sections I0 and II of the holder are providedby extending the front end of the bushing I3 beyond the end of section II and threading it for engagement with the rear end of section I0. Anannular ring I8 may be provided as a washer. If of different color fromthe members I0 and I I, it also serves as a design feature. A cigaretteor cigar holding means may be provided by suitable projections which maybe moulded as a part of the front end of section III, or a separatemember I9 made conveniently of aluminum, may be pressed tightly into theopen end of section I0, permitting this section to be formed simply as astraight tube. This means preferably comprises some form of baille ortrap to prevent tobacco from reaching the front end of the filter I2,such as the forwardly projecting wall 20 of the smoke passage throughthis member.

Figure 6 illustrates means for holding the improved lter of thisinvention in the stem of a pipe. The mouth-'piece or bit member 3| hasan enlarged smoke passage at the front end into which the bushing 32 istightly fitted. This bushing has holding and aligning means 33 andstopping and spacing means 84 for the lter I2 as in Figure 5. The frontend of the bushing is expanded to the same size as the outside diameterof the pipe stem, and is threaded on its inner side for engagement withthe tobacco holding member 34. This member has a smoke passage 35connecting the bowl 35 to the lower section of an enlarged smoke passage31 in the stem portion. This smoke passage has grooves 38 on each sidefor engaging fins 39 for an inner smoke bafe element, illustrated inFigure'a. These fins are attached to a tube 40 and separate the annularchambers connecting only at the rear end 4I where the fins are omitted..The tube 40 has a section cut out of its upper half at the front end toprovide an opening 42 between the upper chamber and the space inside thetube. A washer 43 (illustrated in Figures 6b and 6c) has an opening ofabout the same inside diameter as the tube 40 and has an outsidediameter slightly less than the diameter of the smoke passage 31,thereby making a snug t in the rear end of this chamber and closing thisend of the annular space about the tube 40. This washer is not necessaryto the operation of the smoke baliles or the filter; but its use ispreferred in order to keep smoke from contact with the' threadedsections of the bushing. The washer may also have small projections 44for fitting into the grooves 38. One of such projections may extendbackwards enough to permit the insertion of a nger nail or other thin'instrument in av notch therein when it is desired to remove the washerin order to clean the smoke passages. With the washer and the filterremoved, all smoke passages in the member 34 are easily accessible fromthe rear for cleaning with an ordinary pipe cleaner.

The direction of flow of smoke through the member 34 is indicated byarrows. The front end of the lower half of the tube 40 and the fins 39fit tightly against the wall forming the front end of the smoke passage31, and may project slightly into suitable grooves cut therein, ifdesired. The tube has an inside diameter slightly larger than theoutside diameter of the lter I2, thereby permitting its easy insertionand removal, and is o1 such length that the filter does not project intothe opening 42. I

vOne example of a filter constructed as described above is a filter rollgauze coated with a layer of thin soft absorbent paper, then a thin,perforated waterproof coating and an outer coating of paper, the outsidediameter being 0.170 inch and the length being 11% inches. Althoughindividual tastes vary as to extent of use of tobacco smoke filters, agauze lter of these dimensions normally gives entirely satisfactoryservice during the. smoking of at least 20 cigarettes of the usual size.A suitable holder for such a filter, constructed as bushing I3illustrated in the drawing, has an inside diameter of 0.220 inch,providing a clearance between the filter and bushing of 0.025 inch. Thesection I4 has an inside diameter of 0.1'1 inch, and the section'I5 aninside diameter of 0.16 inch. The bushing may suitably be stamped orspun from f4 inch aluminum tubing of 0.015 inch wall thickness, or itmay be made as an integral part of the bit member II.

This invention is not to be limited to any specific examples orillustrations presented above, all of which are intended solely forpurpose of illustration, but is limited only by the following claims, inwhich it is intended to claim all novelty insofar as the prior artpermits.

I claim:

1. A smoke ltering device comprising a roll of absorbent textilematerial, a coating having an opening therein and made of gas and waterimpervious material, and an outer opaque coating capable of beingstained throughout its thickness by matter absorbed in the filter andtransmitted through said opening.

2. A smoke filtering device comprising a roll of gauze, a coatingcomprising a layer of abspace around this tube into upper and lowersorbent paper, a second layer of gas and moisture impervious materialhaving an opening therein 4 einem 4. Device according to claim 3 inwhich said 1 gether along one edge.

core comprises a plurality of layers of said textile material stitchedtogether along one edge.

5. A smoke nltering device comprising a roll ofgauze about an absorptivecore comprising stitching along one edge of the gauze.

6. Device according to claim v5 in whichaid core comprises two layers otgauze stitched to- JOHN G. TARRANT.

